Flettner Rotor Clause Samples

Flettner Rotor. A Flettner Rotor is a rotating cylinder, which generates a force perpendicular to the flow of whatever fluid it is in (in this case air). The cylinder generates this lift due to a pressure change across the surface caused by the interaction of the fluid flow and cylinder rotation. The background of these is discussed in detail in WP1. A simple diagram of lift and drag forces felt by a Flettner Rotor is given in Figure 73. The Lift force, which is the primary force in this process, can be calculated using Where; ρ = Density of fluid [kg m−3] U = Speed of fluid in the frame of reference of the cylinder [ms-1] A = Cross sectional area [m2] CL= Coefficient of lift [-] The density of air varies according to temperature. For example, at 30°C the density will be 1.1644 kg m−3 whereas at -25°C the density is 1.4224 kg m−3. This change of density of 16% will result in a reduction of 16% in the drag and lift forces. The drag forces can be calculated as: Where; ρ = Density of fluid [kg m−3] U = Speed of fluid in the frame of reference of the cylinder [ms-1] A = Cross sectional area [m2] CD= Coefficient of drag [-] The vectors of these two forces will give a final force and direction with respect to the fluid flow in the frame of reference of the cylinder. The Coefficient of Lift can be calculated for a simplified model in an inviscid fluid as; Where;